As semiconductor integrated circuit (IC) devices continue to shrink in dimension, challenges are posed with respect to packaging the integrated circuitry into microelectronic devices. In some prior art integrated circuitry device, individual IC chips (die) are connected to inner leads of a lead frame by wire bonds. The chip, wire bonds, and inner leads are completely encapsulated for protection with a substance such as plastic or ceramic. Outer leads communicate with the inner leads of the lead frame, but the outer leads typically remain exposed for mounting of the packaged device to external circuitry, such as a printed circuit board. Exemplary constructions are disclosed in U.S. Pat. Nos. 5,734,198, 5,736,783, 5,763,945, 5,818,105 5,117,068, and 5,692,298, the disclosures of which are incorporated by reference herein.
In a conventional construction, a semiconductor die is placed on and bonded to a center die paddle of a lead frame for support. Inner lead fingers of the lead frame are disposed proximate the paddle but do not contact or communicate with the paddle. Rather, wire bonds communicate between contact pads (terminals) on the die and the inner lead fingers of the lead frame by spanning a gap between the die and the fingers. The wire bonds allow for the transmission of electrical signals between the die and the lead frame. The lead fingers allow the chip or die to be electrically connected with other chips or die for providing an operable microelectronic device.
Wire bonds can be problematic for a number of different reasons. First, additional processing steps are needed to ensure that the wire bonds are adequately formed between the lead frame and bond pads on the integrated circuit die. Such processing requires precise placement of the wire bonds or the operation of the integrated circuit die can be compromised. Additionally, because wire bonds are typically very thin electrical connections they can become disconnected and cause operational failure of the finished device.
Accordingly, this invention arose out of concerns associated with providing improved microelectronic devices and methods of forming the same which reduce processing complexities and provide for improved performance.